The invention relates to machines for positioning roof supports in a tunnel.
A previously proposed machine for positioning roof supports in a tunnel has comprised a wheeled base which runs along a floor of the tunnel, the base being provided with a arm pivotally mounted on the base at one end and having a holder for a roof support at the other end. A roof support mounted on the holder is raised from the ground by the arm and positioned in the roof.
It is a disadvantage of this previous proposal that the base running along the floor of the tunnel interfers with the positioning of conveyor belts in the tunnel to remove tunnelled material and also prevents easy access to a heading of the tunnel.
It is an object of the invention to mitigate these disadvantages.
Accordingly, the invention provides a machine for positioning roof supports in a tunnel and comprising a body unit including a track engaging assembly by which the body unit can be suspended from an overhead track, a drive motor for driving the body unit along the track, an arm assembly connected at one end thereof to the body unit for pivotal movement about a horizontal axis and connected at an opposite end thereof to a holder for a roof support and a lifting hydraulic actuator which acts on the arm assembly to pivot the arm assembly about said pivotal axis so that, in use, with the body unit suspended from an overhead track extending along a tunnel, the holder is movable by the lifting hydraulic actuator between a lowered position in which a roof support can be loaded onto the holder and a lifted position in which the loaded roof support is at or adjacent a tunnel roof supporting position.
A machine according to the invention has the advantage that by being suspended from an overhead track, it does not interfere with any floor mounted conveyor in the tunnel and also does not prevent easy access to the tunnel heading.
The roof support may comprise an arch crown rolled steel joist in which case the holder preferably comprises two channel members spaced on opposite sides of a vertical plane including the arm assembly, said channel members, in use, carrying the arch crown so that the arch crown lies in a plane normal to the length of the tunnel before the arm assembly is lifted.
The holder preferably includes a bucket within which a person or persons may stand. The provision of a bucket allows the roof support to be fitted in position in the roof by an operator standing in the bucket. In addition, an operator in the bucket can also undertake other tasks such as stemming and tunnel maintenance.